Dowel structure



March 18, 1952 J WEBB 2,589,464

DOWEL STRUCTURE Filed Sept. 20, 1947 41 "'lll/ Q I6 23 FIG. 1

INVENTOR.

ELMER J W BE= BM immw ATTORNEYS Patented Mar. 18, 1952 UNITED STATES PATENT OFFICE DOWEL STRUCTURE Elmer J. Webb, Newark, N.- Y. Application September 20, 1947, Serial No. 775,255

2 Claims.

' 1 This invention relates to a dowel structure for joints between concrete slabs, such as joints between slabs in concrete highway construction.

The invention consists of an improvement on the dowel structure disclosed in my prior Patent No. 2,183,484, issued December 12, 1939.

These dowel structures are employed to support adjacent or confronting edges of the concrete slabs to keep the top surfaces of the slabs .in alinement and at the same time, the dowel structures permit expansion and contraction of the slabs resulting from seasonal changes in temperature.

This invention has as an object an improved dowel arrangement whereby the dowel rods are more effectively supported where they protrude from the confronting faces of the slabs into the opening or space at the joint between the slabs. and whereby the medial vertically extending portion of the dowel rod positioned in the joint between the slabs is more free to flex when the rods are placed under compression and tension resulting from the expansion and contraction of the slabs.

The invention has as a further object a dowel structure by which the unit can be quickly and conveniently placed transversely of the road grade, and which includes a compressible spacer strip with a plurality of individual dowel structures positioned thereon, the normally flexible strip being rendered rigid for convenient handling and positioning.

The invention consists in the novel features and in the combinations and constructions here- .inafter set forth and claimed.

In describing this invention, reference is had to the accompanying drawings in which like characters designate corresponding parts in all the views.

In the drawings- Figure 1 is a top plan view of a dowel arrangement embodying my invention.

Figure 2 is a vertical sectional view of the structure shown in Figure 1.

Figure 3 is a view taken on line 33, Figure 2.

Figure 4 is' a side elevational view of one of the supporting plates.

Figure 5 is an enlarged view similar to Figure 2.

The joints between the concrete slabs III are formed by a compressible spacer strip I I, usually of impregnated fibrous material, formed at spaced intervals along its length with apertures I- 2 providing openings in the joint between the slabs. A dowel structure is arranged at each opening in the spacer strip and consists of a rod having a vertically extending medial portion positioned in the space between the confronting edges of the slabs, and laterally extending portions embedded in the slabs. The rods are preferably arranged in pairs with the medial portions I3 positioned in the opening I2, and with the lateral portions I4 of the rods extending from the upper part of the opening, and the lateral portions l5 extending from the lower part of the opening. One of the lateral portions, as It, is preferably bent downwardly to form a foot portion I6 engaging the road grade to maintain the dowel structure and the spacer strip II in proper position while the concrete is being poured.

The opening I2 is closed by a plate l8 arranged on each side of the strip I I. These plates are formed with apertured protrusions I9 adjacent the upper and lower sides of the opening I2 respectively, and on opposite sides of the vertical medial line of the plates. The plates are also formed with an elongated depression 20 arranged in vertical alinement with each protrusion I9. The protrusions I9 merge with the plates on a radius 22.

The lateral portions I4, I5, of the rods extend through the apertured protrusions into the slabs and preferably, the radius on which the lateral portions I4, I5, merge with the radial portion I3 is greater than the radius 22.

As previously stated, the spacer strip II is formed with fibrous material to make it compressible when the slabs expand under temperature rise. These strips are accordingly extremely flexible and when a dowel joint unit, consiste ing of a strip with a plurality of dowel structures attached thereto, is moved into position on the road grade, it is difiicult to handle the unit. The strip II fractures easily, and it takes time to line the unit up straight prior to pouring the concrete.

In the arrangement herein disclosed, I mount a channel member 23 on the lower edge of the spacer strip I I, the channel extending the full length of the spacer strip, with the side walls of the channel engaging opposite sides of the strip. The plates I8 are formed along their lower edges with one or more ribs or corrugations 24 which engage and interlock with beads 25 formed on the edges In the structure of my prior patent, the plates crete was poured, and to close the sides of the.

opening in the, spacer strip and, of course, by the depressions in the plates, to provide a space for movement of the medial portion of the rod during expansion and contraction of the slabs. That structure has proven to be entirely satisfactory for ordinary highway construction. However, in some instances where the highway was subjected to unusually heavy truck traffic,

it was necessary to use a dowel rod of larger diameter. This was due to the fact that the plates of my prior structure did not provide the maximum, bear n ne essar or t e. ow rods to carr hesreater ad- In. t e. s ructur herein. scri e the p at .8.- prov e. a s i up stru ur wh adequately su rts the r ds espec l y w en. th e der c mpressi n; It w l e unde st d th d wnw rd. p ssu e. on. qneyslab will pla e o red f each pair under. ompr s i and the h r r d. und r tens on.- or example i Fi ur 2,. i ownw rd; press re. is. appl to e right han slab; ;Q- .-'t1. .e. med al; portio s o the rod, shown section, will be under compression, and the medial portion of the other e hown in ele ation, will. be und r tensionhe. an. u der compr s ion. bear a ain th outsideportion of the'protrusions 59, the plates acting. esfsti rups. and, inasmuch as they are m edd d inthe conpreta. take the major tion of the load off from the concrete surroundns t e. lateral; extensions 1:4, is, .of the rod.

= This results in obtaining themaximum compressive. an ensile trength. or the. rods at the road joints, whereby rods of the same diameter effectively carry "a much greater load without failure. of. the'rods, or failure of the concrete in, the confronting faces of the slabs.

The plates .18 are embedded in. the concrete slabs and inasmuch.- as. the protrusions l9 ex-- tend into the slab, this.- critical point of bearin l cated within. the. slab. In view of the factthatgthe: radius. 22; of the protrusions is ess, than the; inside radius at the bend of the rod, thisv allows. a slight, straightening of the bar at the, radius, rather than stretching the metal; andi'thlls; causing serious stresses in the r and. at'the' same time providing a. continuous bearing forthe bar atthe portion under tension'dur' .gthecomplete cycle of expanion intermediate the. upper and. lower edges thereof; a plate arranged on each side of the strip in register with said opening and forming a closure therefor, saidplates being embedded in the confronting faces ofthe slabs respectively and. each 'of said plates being formed with a pair of. apertured protrusions arranged in vertically 'spaced relation and extending into the slabs-and merging with; the plates on an arc, a pair of: dowel rods; each having lateral portions extending in opposite directions from a medial portion andbeingjoined thereto on an are having a radius greater; than theradii of said protrusions, said rods being positioned with 4 their medial portions extending vertically in the opening in the spacer strip and with their arcs engaging the arcs of said protrusions and with their lateral portions extending through said apertured protrusions in the plates, one of said rods having a lateral portion extending through the lower protrusion in one plate and the other rod of said pair having a lateral portion extending through the upper protrusion in said plate, the other lateral extensions of said pair of rods extending through the extrusions of the other plate in the reverse order,

and each of said plates being formed with a recess arranged in register with the apertured protrusion in the other plate and forming a space Within which to. permit movement of the medial portions of said rods during expansion of said slabs. V

2. A pavement joint dowel structure supporting adjacent slabs; of concrete comprising a spacer strip positioned between the confronting ends of the slabsandhaving an opening intermediate the upper and lower, edges thereof, a plate arranged onea-ch side of the strip in register with said opening and forminga 010- sure therefor, said plates being embedded in the confronting faces of the slabs respectively and each of said plates being formed with a pair of apertured protrusions arranged in vertically spaced relation and extending. into the slabs and merging with the plates on an arc, a pair of dowel rods, each having lateral: portions extending in opposite, directions from a medial portion and being joined thereto on an are having a radius greater than the radii of said protrusions, said rods being positioned with their medial portions extending vertically in the opening in the spacer strip and with their arcs engaging the arcs of said protrusions and with their lateral portions extending through said apertured protrusions in the plates, one of said rods having a. lateral portion extending through the lower protrusion in one plate and the other rod of said pair having a lateral portion extending through the upper protrusion in said plate, the other lateral extensions of said pair of'rods extending through the extrusionsof the other plate in the reverse order, each of; said plates being formed with a recess arranged, in register. with the apertured protrusion in the other plate and forming a space, within which to permit movement of, the medial portions. of said rods during expansion of said slabs, and a reinforcing channel member positioned on the lower edge of said strip with the sides. Qf the 7 channel frictionally engaging the opposite Sides file of this patent: V

of the strip, means operable tQ' lamp saidplates onto the strip, said plates and. channel memher having means. c ooperable to interlock the same upon operation of said. clamping. means.

ELMER. J. WEBB.

REFERENCES CITED The following references are of record in the V UNITED i STATES PATENTS Number 

